| Uranus is the third largest planet in the solar system and is the seventh planet from the Sun. It is a cold planet made of gas. One special thing about Uranus is that it's rotation axis nearly coincide its orbit around the Sun. Because of this, Uranus experiences 42 years of light followed by 42 years of darkness in the pole area. Although it is quite a bright object in the sky, it is not until 1781 that it is discovered by William Herschel. The atmosphere is composed of hydrogen, helium, methane and other elements. Uranus has a beautiful blue color because the upper atmosphere is composed of methane and it absorbs red light. Uranus has 11 rings and has at least 21 satellites. Both its rings and satellites are difficult to observe. Even the largest satellite has only a magnitude of 14. Since Uranus is tipped on its side, its rings are not obvious, it cannot be observed using amateur telescopes. The first nine rings of Uranus was discovered in 1977. Two other new rings were discovered during the Voyager's encounter. The outermost epsilon ring is composed mostly of ice boulders. There are also thin rings or incomplete arcs. Individual ring particles are of low reflectivity. |
|
Uranus Statistics:
Mass (kg): 8.68x1025 Diameter (km): 51118 Average Density (kg/m3): 1290 Escape Velocity (m/sec): 21300 Rotation Period (Earth days): 17.9 Tilt of Axis (o): 97.9 Orbit inclination (o): 0.77 Average Surface Temperature (oF): -357 Atmospheric Components: 83% Hydrogen, 15% Helium, 2% Methane Number of Satellites: at least 21 (Ariel, Belinda, Caliban, Cordelia, Cressida, Desdemona, Juliet, Miranda, Oberon, Ophelia, Portia, Puck, Rosalind, Sycorax, Titania, Umbriel and other moons) Number of Rings: 11 (1986U2R, 6, 5, 4, Alpha, Beta, Eta, Gamma, Delta, 1986U1R, Epsilon) |
 |
Uranus' Satellites
| Moon | Radius (km) | Mass (kg) | Distance (km) | Discoverer | Date |
|---|---|---|---|---|---|
| Cordelia | 13 | ? | 49,750 | Voyager 2 | 1986 |
| Ophelia | 16 | ? | 53,760 | Voyager 2 | 1986 |
| Bianca | 22 | ? | 59,160 | Voyager 2 | 1986 |
| Cressida | 33 | ? | 61,770 | Voyager 2 | 1986 |
| Desdemona | 29 | ? | 62,660 | Voyager 2 | 1986 |
| Juliet | 42 | ? | 64,360 | Voyager 2 | 1986 |
| Portia | 55 | ? | 66,100 | Voyager 2 | 1986 |
| Rosalind | 27 | ? | 69,930 | Voyager 2 | 1986 |
| Belinda | 34 | ? | 75,260 | Voyager 2 | 1986 |
| 1986U10 | 20 | ? | 75,000 | Karkoschka | 1999 |
| Puck | 77 | ? | 86,010 | Voyager 2 | 1985 |
| Miranda | 235.8 | 6.33e+19 | 129,780 | G. Kuiper | 1948 |
| Ariel | 578.9 | 1.27e+21 | 191,240 | W. Lassell | 1851 |
| Umbriel | 584.7 | 1.27e+21 | 265,970 | W. Lassell | 1851 |
| Titania | 788.9 | 3.49e+21 | 435,840 | W. Herschel | 1787 |
| Oberon | 761.4 | 3.03e+21 | 582,600 | W. Herschel | 1787 |
| Caliban | 30 | ? | 7,100,000 | Gladman | 1997 |
| 1999U1 | 20 | ? | 10,000,000 | Kavelaars | 1999 |
| Sycorax | 60 | ? | 12,200,000 | Nicholson | 1997 |
| 1999U2 | 15 | ? | 25,000,000 | Gladman | 1999 |
| 1999U3 | 20 | ? | Holman | 1999 |
Uranus' Rings
| Name | Distance (km) | Width (km) | Thickness (km) | Mass |
|---|---|---|---|---|
| 1986U2R | 38,000 | 2,500 | 0.1 | ? |
| 6 | 41,840 | 1-3 | 0.1 | ? |
| 5 | 42,230 | 2-3 | 0.1 | ? |
| 4 | 42,580 | 2-3 | 0.1 | ? |
| Alpha | 44,720 | 7-12 | 0.1 | ? |
| Beta | 45,670 | 7-12 | 0.1 | ? |
| Eta | 47,190 | 0-2 | 0.1 | ? |
| Gamma | 47,630 | 1-4 | 0.1 | ? |
| Delta | 48,290 | 3-9 | 0.1 | ? |
| 1986U1R | 50,020 | 1-2 | 0.1 | ? |
| Epsilon | 51,140 | 20-100 | < 0.15 km | ? |